The Black Family Tree is, of course, one of the most popular "extras" Rowling has given fans, containing lots of non-book information.
I downloaded the Family Tree Builder, and it proved addictive. (I now have family trees for several other characters for whom you'll never have any reason to care about the names of their grandparents.) I tried out several similar tools, and this one was the easiest (free) one, so I recommend it to writers who want to create family trees for their characters.
I hereby present the (edited -- sorry, some details can't be revealed yet) Thorn family tree. Yes, some of it is quite relevant to Alexandra's story. Most of these names will probably never be mentioned in the books, though.
AQATDR progress report:
I am approaching the climax and sometimes have spurts of productivity for several hours at a time. Unfortunately, this can't continue (there are other things I really should be doing besides writing fan fiction), but I can feel myself nearing the end in the not-too-distant-but-I'm-still-unwilling-t
So, the word count now stands at 160K, at chapter 24. I am expecting (which means, that's what I've got very loosely outlined) to wrap up the story in five more chapters, but you know how that goes. Twenty-nine chapters -- maybe, but I won't be surprised if a few more chapters insert themselves.